Pile driving system and pile for engagement with said system

ABSTRACT

A system for controlling pile orientation comprises a pile ( 14 ) and a pile guide ( 20 ) for supporting the pile as it is driven into a substrate, the pile guide comprising a base frame ( 10 ) and a pile guide member ( 22 ) mounted on the base frame. The pile ( 14 ) and the pile guide member ( 22 ) have slidaby interengaging profiles ( 30, 40 ) comprising first and second parts ( 32, 42 ), which are configured to axially rotate the pile to correct any misorientation relative to the pile guide as the parts slide past each other, and third and fourth parts ( 34, 44 ), which are configured to maintain a predetermined orientation of the pile relative to the pile guide once any misorientation has been corrected by interengagement of the first and second parts.

BACKGROUND OF THE INVENTION

1. Field of the Invention

The invention relates to pile driving, and more particularly, but notexclusively, to underwater pile driving, e.g. for stabbing pilesdirectly into the seabed.

2. Description of the Background Art

It is known to provide a guide for aligning a pile with the surface of asubstrate into which the pile is to be driven and to provide stabilityfor a piling hammer. Particularly when piling underwater there is theproblem that after the pile has been introduced into the seabed or thelike, the guide must be removed to allow the pile to be driven into itsfinal position. This guide removal is time consuming and thus expensive.Accordingly, the present applicant proposed in International patentpublication WO99/11872 a pile guide which allows pile driving tocontinue from start to finish without any need to interrupt driving toremove the guide.

The pile driving apparatus described in WO99/11872 comprises a pileguide member which is supported on a base frame, a plan view of which isreproduced in FIG. 1. The base frame (10) has a substantiallyrectangular footprint (made up of a welded framework of girders andmudmats) with a centrally-placed aperture (12) through which a pile (14)is guided. The base frame 10 thus surrounds the pile (14). It will beseen however, that the base frame is formed with an aperture or slot(16) extending through the frame from its exterior to the centralaperture (12) and through which a tether or rigging (18) fixed to thepile (14) can be passed.

In practice, it is important to orientate the pile so that thetether/rigging (18) will be aligned in a predetermined directionaccording to the intended use of the pile (14). Until now, a set pileorientation has been achieved using so-called orientation plates on thepiles which engage a guide plate system in the pile guide member of thepile guide. The orientation plates are positioned on the piles in aknown orientation relative to the tether/riggings couplings provided onthe piles. In use, the orientation plates will engage the guide platesystem as each mis-orientated pile is introduced into the pile guidemember. The guide plate system forces the orientation plates to follow ahelical path as the pile is further lowered through the pile guidemember, causing the pile to rotate about its axis until the desiredorientation relative to the base frame is achieved.

The present applicant has appreciated that more precise control of theorientation of piles being driven into a substrate (e.g. seabed) may bedesirable, particularly in high swell conditions producing heavesituations.

In accordance with a first aspect of the present invention, there isprovided a system for controlling pile orientation comprising: a pile;and a pile guide for supporting the pile as it is driven into thesubstrate, comprising a base frame and a pile guide member mounted onthe base frame, the pile and pile guide member having slidablyinterengagable profiles comprising first and second parts which areconfigured to axially rotate the pile to correct any mis-orientationrelative to the pile guide as the parts slide past each other;characterised in that the interengaging profiles further comprise thirdand fourth parts which are configured to maintain a predeterminedorientation of the pile relative to the pile guide once anymis-orientation has been corrected by interengagement of the first andsecond parts.

The third and fourth parts prevent the orientation of the pile fromchanging after the first and second parts have cleared each other as thepile is driven into the substrate. The third and fourth parts may beconfigured to engage each other before the first and second parts slidepast and disengage each other. In this way, there is no risk that thepredetermined orientation of the pile will not be maintained when thefirst and second parts disengage. This may be particularly important inheave situations which may produce periodic upward movements in the pilerelative to the pile guide. In the conventional arrangement, once thefirst and second parts have slid past one another, any newmis-orientation in the pile may cause the first and second parts to jamagainst each other during heave-induced, relative upward movement.

The interengagable profiles (e.g. second and fourth parts) on the pileguide may be contiguous or may be spaced apart. The interengagableprofiles (e.g. first and third parts) on the pile are spaced apart alongthe length of the pile.

The third and fourth parts may comprise a plate-like member and achannel in which the plate-like member is a sliding fit. The plate-likemember may be mounted on the pile, and the channel may be provided on aninner periphery of the pile guide member.

The channel may have an upper flared opening for first receiving theplate-like member as the pile is lowered through the pile guide. Thechannel may also have a lower flared opening for re-engaging theplate-like member if the pile rises up through the pile guide (e.g.during heave situation).

The channel may be formed between a pair of spacer plates, the spacerplates being configured to centre the pile in the pile guide member.

The first and second parts may comprise an orientation plate and a guideplate system defining a helical pathway for the orientation plate. Theorientation plate may be mounted on the pile, and the guide plate systemmay be provided on an inner periphery of the pile guide member. Theguide plate system may define a pair of helical pathways of oppositesenses of rotation, which define a tapering channel therebetween forcorrecting any mis-orientation in the pile. The tapering channel mayhave a flared portion at its lower end for re-capturing the orientationplate should the pile move upwards relative to the pile guide after thefirst and second parts have slid past each other.

In another aspect of the present invention, there is provided a pile fordriving into a substrate, the pile comprising: an elongate body with aleading end and a trailing end; a coupling for receiving a tether, thecoupling being located towards the trailing end; a first memberprojecting radially outwardly from the body, the first member beinglocated towards the leading end; and a second member projecting radiallyoutwardly from the body, the second member being axially spaced towardsthe trailing end from the first member.

The coupling may be angularly offset (e.g. 90°) relative to at least onemember. The first and second members may be angularly aligned. The firstmember and/or the second member may be plate-like with the plane of theor each member parallel to the longitudinal axis of the body.

BRIEF DESCRIPTION OF THE DRAWINGS

An embodiment of the invention will now be described by way of examplewith reference to the accompanying drawings, in which:

FIG. 1 is a plane view of a prior art base frame;

FIG. 2 is a side view of a prior art pile guide for underwater piledriving;

FIG. 3 is an exploded view showing a pile (from one side) and pile guidemember (in vertical section) of a system embodying the presentinvention; and

FIG. 4 is a view showing the pile of FIG. 3 from another side.

DESCRIPTION OF SPECIFIC EMBODIMENT

FIG. 2 shows a pile guide (20), known from WO99/11872, which comprises abase frame (10) (as per FIG. 1) and a pile guide member (22) mounted onthe base frame (10). A pile (14) (as per FIG. 1) is supported by thepile guide member (22) whilst being driven into the substrate (24) (e.g.seabed).

The pile (14) and the pile guide member (22) have respectivelyinterengaging profiles (30,40) different parts of which either correctany mis-orientation in the pile (14) relative to the pile guide (20) ormaintain a predetermined orientation between the pile (14) and pileguide (20). Specifically, the interengaging profiles (30,40) include afirst part (32) on pile (14) which engages a second part (42) on theinner periphery of pile guide member (22). Furthermore, theinterengaging profiles (30,40) include a third part (34), locatedrearwardly of the first part (32) on pile (14), and a fourth part (44)on the inner periphery of the pile guide member (22). In use, the firstpart (32) engages the second part (42) as the pile (14) is lowered intothe pile guide member (22). Any mis-orientation in the pile (14) iscorrected as the first part (32) slides against the second part (42). Asthe correctly orientated pile (14) is further lowered, the third part(34) will engage the fourth part (44) to maintain the orientation of thepile (14) relative to the pile guide (20). The structure of the variousparts (32,34) and (42,44) will now be considered in more detail.

The Pile (14)

The pile (14) includes a coupling (50) for a tether (not shown) which islocated towards the trailing end (52) of the cylindrical body (54) ofthe pile (14). The first part (32) of the interengaging profile (30)comprises a primary orientation plate (56) which is aligned parallel tothe longitudinal axis AA of the pile (14) and which projects radiallyoutwardly from the body (54). The orientation plate (56) has a curvedleading edge (58) (closest to leading end (60) of the body (54)) andchamfer (62) on its trailing edge (64). The other part (34) of theinterengaging profile (30) comprises a secondary orientation plate (70)which is aligned with, but spaced rearwardly of, the primary orientationplate (56). Again, the leading edge (72) of the orientation plate (70)is rounded. Both orientation plates (56,70) are angularly offset by 90°from the coupling (50).

The Pile Guide Member (22)

The pile guide member (22) has a generally cylindrical housing (80)which includes a plurality of spacers (82) for centering the pile (14)in the pile guide member (22). One part (42) of the interengagingprofile (40) includes a pair of helical guide plates (84) of oppositesenses of rotation which define a tapering channel (86) for correctingany mis-orientation of the pile (14). The tapering channel (86) tapersto a neck region (89) which is flared at its lower end (90). The otherpart of (44) the interengaging profile (40) includes a pair of parallelguide plates (92) with a flared opening (94) at its upper end (96). Theguide plates (92) have a spacing function just like spacers (82).

In use, the primary orientation plate (56) engages on the helical guideplates (84) as a mis-orientated pile (14) is lowered into the pile guidemember (22). The primary orientation plate (56) slides against theengaged helical guide plate (84), causing the pile (14) to rotate into apredetermined orientation as it is further lowered. Before the primaryorientation plate (56) exits the channel (86) through the neck region(89), the secondary orientation plate (70) slides between the parallelguide plates (92), maintaining the predetermined orientation of the pile(14).

1. A system for controlling pile orientation comprising: a pile; and apile guide for supporting the pile as it is driven into a substrate,comprising a base frame and a pile guide member mounted on the baseframe, the pile and pile guide member having slidably interengagableprofiles comprising first and second parts which are configured toaxially rotate the pile to correct any mis-orientation relative to thepile guide as the parts slide past each other; characterized in that theinterengaging profiles further comprise third and fourth parts which areconfigured to maintain a predetermined orientation of the pile relativeto the pile guide once any mis-orientation has been corrected byinterengagement of the first and second parts.
 2. A system according toclaim 1, in which the third and fourth parts are configured to engageeach other before the first and second parts slide past and disengageeach other.
 3. A system according to claim 1, in which the third andfourth parts comprise a plate-like member and a channel in which theplate-like member is a sliding fit.
 4. A system according to claim 3, inwhich the plate-like member is mounted on the pile, and the channel isprovided on an inner periphery of the pile guide member.
 5. A systemaccording to claim 3, in which the channel has an upper flared openingfor first receiving the plate-like member as the pile is lowered throughthe pile guide.
 6. A system according to claim 1, in which the channelfurther comprises a lower flared opening for re-engaging the plate-likemember if the pile rises up through the pile guide.
 7. A systemaccording to claim 3, in which the channel is formed between a pair ofspacer plates, the spacer plates being configured to center the pile inthe pile guide member.
 8. A system according to claim 1, in which thefirst and second parts comprise an orientation plate and a guide platesystem defining a helical pathway for the orientation plate.
 9. A systemaccording to claim 8, in which the orientation plate is mounted on thepile, and the guide plate system is provided on an inner periphery ofthe pile guide member.
 10. A system according to claim 8, in which theguide plate system defines a pair of helical pathways of opposite sensesof rotation, which define a tapering channel therebetween for correctingany mis-orientation in the pile.
 11. A system according to claim 10, inwhich the tapering channel has a flared portion at its lower end forre-capturing the orientation plate should the pile move upwards relativeto the pile guide after the first and second parts have slid past eachother.
 12. A pile for driving into a substrate, the pile comprising: anelongate body with a leading end and a trailing end; a coupling forreceiving a tether, the coupling being located towards the trailing end;a first member projecting radially outwardly from the body, the firstmember being located towards the leading end; and a second memberprojecting radially outwardly from the body, with the second memberbeing axially spaced towards the trailing end from the first member, andwith the first and second members being configured to engage a pileguide and to orientate the pile in dependence on engagement with thepile guide.
 13. A pile according to claim 12, in which the coupling isangularly offset relative to at least one member.
 14. A pile accordingto claim 12, in which the first and second members are angularlyaligned.
 15. A pile according to claim 12, in which the first member isplate-like and defines a plane with the plane of the first member beingparallel to a longitudinal axis of the body.
 16. A pile according toclaim 12, in which the second member is plate-like and defines a plane,with the plane of the second member being parallel to a longitudinalaxis of the body.